Esters of Phosphorus Acid

The esters of phosphorus acid are obtained by condensation of triphenylphosphites or trialkylphosphites with various polyols, such as dipropylene glycol (reaction 18.10) [5, 

The resulting tris(dipropylene glycol) phosphite has an hydroxyl number of 395 mg KOH/g and a phosphorus content of 7.2% [5, 31, 33]. 

Unfortunately, trialkyl phosphites are extremely susceptible to hydrolysis, being more rapidly hydrolysed than the ortho-phosphoric esters. Due to their susceptibility to hydrolysis, the phosphorus polyols with phosphite ester structure are not used at the moment. 

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Haloacetyl groups have also a synthetic potential. Thus, pesticidal (alkylthio)-vinyl esters of phosphorus acid derivatives have been prepared by the introduction and subsequent displacement of two chlorine atoms in the acetyl moiety attached to the furazan ring (Scheme 69) [73GEP(0)2144393]. 

The catalytic activity of surfactant micelles and the effect of the concentration of reagents in micelle catalysis are tested on hydrolysis of esters of phosphorus acids [25],... 

As with other reactions, silyl esters of phosphorus acids constitute an important and useful category of reagents for conjugate addition reactions. With aldehydes, ketones, and esters, the silyl ester linkage is transferred to the carbonyl oxygen, facilitating the completion of the reaction, generating the free carbonyl or ester upon workup with a protic solvent (Equation 3.25). 

In many examples, it is not necessary to prepare the phosphorane. Instead, the dicarbonyl compound is heated with a trialkyl or triaryl ester of phosphorus acid or, less commonly, with a diester of a phosphonous acid (RP(OH)2, where R is an organic group). For example, when the thioester 301 is heated with dipropyl ethylphosphonite the 2-substituted carbapenem 302 is produced in 80% yield (Equation 32) <1997CPB1439>. This general method has been used to prepare 2-sulfide-substituted 1/3-methylcarbapenems <2000CPB126, 2001SC587> and O-protected 2-hydroxymethyl derivatives < 1999JA11261 >. 

Topics relevant to the present Chapter are discussed in general reviews concerned with phosphorus-containing isocyanates, and with the synthesis and uses of organosilyl esters of phosphorus acids. ... 

Pudovik, A.N., Anomalous reaction of a-halo ketones with esters of phosphorous acid. Part 4. Reactions of esters of phosphorus acid with mono- and dichloroacetylacetone, phosphonoacetone, and acetoacetic ester, Zh. Obshch. Khim., 26, 2238, 1956 Chem. Abstr., 51, 1827a, 1957. 

Abramov, V.S., and Kapustina, A.S., Reaction of dialkyl esters of phosphorus acids with aldehydes and ketones. Part 13. Esters of a-hydroxy-P-chloroisopropylphosphonic and 1,2-epoxyisopropylphos-phonic acids, Zh. Obshch. Khim.. 27, 1012, 1957 Chem. Abstr, 52, 36661, 1958. 

Whetstone, R.R., and Harman, D., Insecticidally active esters of phosphorus acids and preparation of the same. Shell Oil, U.S. Patent Appl. US 2956073, 1960 Chem. Abstr, 55, 6380a. 1961. 

Pudovik, A.N., and Sitdikova, F.N., Addition of partial esters of phosphorus acids to nitroisoamylene and ethyl vinyl sulfone, Dokl. Akad. Nauk SSSR, 125, 826, 1959 Chem. Abstr, 53, 19850c, 1959. 

Inch and his co-workers continue to use carbohydrate derivatives in the synthesis of chiral esters of phosphorus acids and for studies of the displacement reactions of these esters. For example, the tetrahydro-l,3,2-oxazaphosphorine-2-ones (74) and (76) were synthesized and cleaved to give the chiral phosphonate (75) and the chiral phosphate (77), as illustrated in Schemes 35 and 36. 2-Thiones related to (74) and (76) were also prepared and used to obtain such chiral thiophosphates as (78) from (79). Attack on the acyclic S -methyl phos-... 

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